In the massacre, 500 troops of the U.S. 7th Cavalry surrounded an encampment of around 450 Lakota Sioux of the Miniconjou and Hunkpapa tribes, near Wounded Knee Creek. The cavalry was to escort them to a train for removal to Nebraska. One day prior, the Lakota tribes ended their protracted flight to come in to the Pine Ridge Agency. During disarmament before removal, a deaf tribesman could not surrender his rifle, which set off reactions leading to chaos and shooting.

When over, about 300 Lakota Sioux men, women, and children were killed, then buried in a mass grave. 25 cavalrymen died, and those remaining pursued and killed many of the unarmed Lakota that had escaped the massacre.